When did Leonardo da Vinci invent the airscrew?

Why and how are digital graphics used in the entertainment industry? Why does sound carry better in the fog? Is radiography and CT scan the same What is Radiography of the uterus and oviducts after a contrast medium is injected into those organs? If you take this aesthetic view you believe that the meaning message or feeling expressed in an artwork is the most important part? What are some colours that begin with r? Did Georgia O'Keeffe have a favorite color? What are the rear hub nut torque settings on a Renault clio? How many times does 8 go into 38? In the northern hemisphere planetary winds blowing from north to south are deflected or curved toward the west What is this delection caused by? If rocks made planets what made space? Why did Andy Warhol like to use celebrities in his art work? What are three types of perspective drawings? When did Claude Monet die? What does feathers hanging from a barbed wire tattoo mean? What was the African period with Picasso? Where are the headquarters of Bollywood? What is a thermo switch? What Comedian said God Bless your pea pecking heart? How can you tell that Indian artists were respected? How do you draw Spain?